Field
The described technology generally relates to electronics, more specifically to rail-to-rail amplifiers.
Description of the Related Art
For certain applications, such as high-precision amplification, it can be desirable for an amplifier to have a relatively low input offset voltage. An amplifier, such as an operational amplifier or instrumentation amplifier, can include chopper circuitry for reducing the amplifier's input offset voltage. To aid in achieving a relatively low input offset voltage, certain amplifiers can use auto-zeroing and/or chopping schemes. A chopper amplifier can have a different input offset in different transistor configurations. For example, prior to chopping, the chopping amplifier can have different amounts of input offset voltage in different transistor configurations. The input offset voltage of the chopper amplifier can change with different transistor configurations due to manufacturing mismatch between transistors, such as manufacturing mismatch associated with process variation.
An amplifier that is designed to drive a switched capacitive load such as the input capacitor of a sigma-delta type of analog to digital convertor (ADC) or a successive approximation register (SAR) type of ADC should have accuracy in output voltage over the full range of inputs and outputs while preserving bandwidth large enough to deliver the output voltage in the allocated sampling period. Furthermore, such an amplifier can incorporate other features such as chopping for low offset and drift, which may benefit from stabilization or auto-zeroing for the chopping mechanism.